Italy's Valentino Rossi surprised himself but not his main MotoGP championship rival Australia's Casey Stoner with a barnstorming victory in the Dutch Grand Prix at Assen.

In a tough race yesterday, Stoner said he saw Rossi's unstoppable surge of speed coming, while Rossi admitted that he had to convince himself he could inflict defeat on his young Australian rival.

It was only the third time this season Rossi has finished ahead of Stoner.

And with his controlled ride into second place, Stoner maintains a 21-point lead after nine races, the halfway point of the 18-race season.

Reigning world champion Nicky Hayden finished third, his first podium of the season.

Rossi stormed to an amazing victory after starting 11th on grid, riding in the commanding style that has been his trademark for 61 career MotoGP wins.

Stoner and Ducati have won five races to Rossi's three this season and he leads by 185 points to 164 over his Italian rival.

"I've only been off the podium twice in nine races so I can't complain about this result," said Stoner after succumbing to Rossi's late race charge four laps from the finish.

"I knew Valentino could come from 11th on the grid. You can never rule Valentino out. He can pull it out day-in, day-out at this level.

"I saw him on the big TV screens around the track, he was chasing me down pretty hard, he had a faster pace."

Stoner had bolted from the front row to dominate the lead for 22 of 26 laps, but could not hold out Rossi after his Ducati was pushed around by strong winds.

"I had a big problem with the wind and I lost some confidence on the brakes and for the effort I was putting in I didn't get the lap times I expected," Stoner said.

Rossi started the race with no thought of winning but convinced himself otherwise with a series of clinical, high-speed overtaking moves on Hayden and Dani Pedrosa.

Rossi took 12 laps to get into second place and then another 10 to wear down Stoner for the victory.

"I used a lot of energy to catch Casey, I needed a rest, and then finally I said to myself you are riding very, very good so I went for the win," Rossi said.

"This was an important win for me. Casey had won the past two races and I needed to stop his run, he was very confident, and to catch some points."

After starting from pole position Australian rider Chris Vermeulen was unceremoniously bumped out of seventh place by wild Frenchman Randy de Puniet.

Vermeulen recovered from his off-track excursion to finish 16th, while de Puniet's Kawasaki barrel-rolled into a gravel trap.

Rider Classifications:

MotoGP newcomer Anthony West scored his first top-10 finish with ninth place on his Kawasaki.AAP

In Italian: Vale, il flirt più bello: un bacio alla vittoria

A metà motomondiale, il successo di Assen porta Rossi a 21 punti da Stoner e riapre la corsa al titolo perché in condizioni di pista normali, Yamaha e Ducati sono alla pari e la differenza la faranno i piloti.

Le odiate gomme Michelin di Donington, stavolta hanno fatto la differenza. Non solo loro, certo, come non solo loro avevano causato il declino di una settimana fa. Lo sa bene Valentino Rossi, vincitore ad Assen, Jerez e Mugello, tanto da poter affermare due incontrovertibili verità: "Nelle ultime quattro gare io e Stoner abbiamo fatto gli stessi punti". Ma è anche vero che... "La prossima volta che piove ne perdo 13".